At the request of the SOD Science Lab, Sora Honda conducts an experiment to prove the link between nipple and penis sensitivity. She tests various stimulations like rolling, pinching, kneading, licking, and sucking, and checks the penis reaction with her eyes, mouth, and pussy. Although she hasn't had any private sex lately, she unconsciously touches her nipples as if to make the penis more sensitive. This is a research record from a production department AP who is that type.